Technical Field
[0001] Embodiments of the present disclosure relate to position verification systems, and
more particularly, to brachytherapy systems for verifying the positioning of a conduit
configured to receive a radiotherapy source once the conduit is within a patient.
Background Information
[0002] Brachytherapy is a method of treating cancer by placing one or more radiotherapy
sources in or by an area of tissue requiring treatment. Delivering radiation directly
and accurately to the target treatment area may allow a clinician to administer higher
doses of radiation while decreasing the impact on surrounding, healthy tissue.
[0003] In a typical brachytherapy treatment method, prior to treatment delivery, one or
more conduits, for example, a brachytherapy applicator, a needle, a tube, or a catheter,
is positioned within a target treatment area. The conduit is connected to a source
of treatment, and a radiotherapy source is delivered from the treatment source and
through the conduit into the treatment area. The conduits are positioned within the
patient to deliver the radiotherapy source to suitable, pre-determined treatment locations.
The treatment source may be a mechatronic or computerized device (e.g., an afterloader),
or the treatment may be delivered manually, and the radiotherapy source may either
be a small X-ray generating device, a high dose-rate radioactive source, or a low
dose-rate radioactive source for use with longer, shorter, or even permanent dwelling
times within the patient.
[0004] To increase the effectiveness of brachytherapy, clinicians aim to administer an optimal
dosage of radiotherapy source to the target tissue. Following diagnosis, brachytherapy
treatment may include multiple stages. Imaging of the patient anatomy and disease
anatomy (e.g., tumor location, size, shape, density, orientation) may be analyzed
to determine the appropriate regions to administer treatment to. During a treatment
preparation and/or planning stage, the desired placement, positioning, and orientation
of one or more conduits to deliver the treatment to these target treatment regions
may then be determined. Additionally, one or more dwell positions (i.e., locations
where the radiotherapy source will remain for a period of time) within each conduit
may be mapped in order to achieve a desired dose distribution. During these stages,
conduits, which may take the form of an applicator (e.g., having one or more individual
conduit channels), needles, tubes, or catheters, may be inserted into a patient, and
imaging may be used to confirm the position of the conduits. Next, during a treatment
delivery stage, one or more radiotherapy sources may be delivered to the conduits,
and the patient may undergo radiation treatment.
[0005] Movement or misalignment of one or more conduits may affect the amount of radiation
treatment delivered to the target tissue. Misalignment could cause delivery of treatment
to the wrong area or delivery of the wrong dosage of treatment to the target area.
Yet, there is often no convenient way to verify positioning of the conduits after
the treatment preparation/planning stage to confirm that the treatment will be delivered
as planned.
[0006] For example, an applicator may be inserted into a patient for treatment planning,
and medical imaging may be used to assess positioning of the conduits. Based on this
information, a healthcare provider may determine the location of the dwell positions.
Imaging and/or tracking devices and/or processing software may be used to assist with
the treatment planning based on the location of the applicator within the body. Once
treatment preparation and planning are complete, the patient may be moved into a different
room for treatment delivery or otherwise prepared for treatment delivery. The treatment
delivery room may include shielding to accommodate use of radioactive materials and
may not be compatible with the imaging and/or tracking devices used during treatment
planning. Accordingly, the treatment delivery system (e.g., afterloader) may determine
radiotherapy source positioning based on indirect measurements, such as the predetermined
dwell positions, saved imaging data, the length of the conduits, the distance that
the source has been inserted into the conduits, and the connection of transfer tubes
to the conduits. Yet, inaccuracies may occur when relying on secondary measurements.
For example, any snaking, bunching, or slack that may be created as a wire with a
source or sensor is fed into the conduit may result in inaccurate determinations of
how far the source or sensor has been inserted and where in the conduit it is located.
Thus, following insertion of the conduit into the body for treatment planning purposes,
the conduit may shift within the body, and current systems may not be able to directly
determine spatial positioning of the conduit. Consequently, current systems may be
unable to directly or accurately verify the ultimate location of the radiotherapy
source when delivered to the conduit. Shifting of the conduit after the imaging during
treatment planning or preparation may go undetected, resulting in inaccurate radiation
treatment for the patient.
[0007] Additionally, it may be difficult or impossible to synchronize positioning data across
the various systems, resulting in potential undetected discrepancies or inefficiencies.
For example, treatment delivery systems, such as afterloaders, may use one-dimensional
data, like dwell positions, the number of conduits, and/or the length of the conduits,
to determine positioning. Image processing/planning software may use image data to
create their own position definitions. Three-dimensional tracking systems, such as
electromagnetic tracking, optical tracking, and other multiple degrees-of-freedom
sensor systems may use references and may determine positioning based on relative
measurements and/or calibration. Because each system measures positional information
differently, it may be difficult, if not impossible, to merge or synchronize this
data.
[0008] Further, current methods of position verification, including medical imaging (e.g.,
radiography, X-ray, MRI, ultrasound), electromagnetic tracking, optical shape sensing,
or in vivo dosimetry may be expensive, complex, unwieldy, may disturb the workflow,
or may cause harm or discomfort to the patient. Additionally, these devices may not
be integrated into the treatment delivery system and consequently their feedback cannot
be easily or safely used to interrupt or adjust treatment delivery if an inconsistency
is detected as treatment occurs.
[0009] Additionally, multiple catheters or needles may be inserted into a patient or an
applicator may include multiple conduit channels. Each conduit may have unique shapes,
lengths, sizes, etc., and each conduit may need to be connected to an afterloader
in a specific orientation in order to deliver the radiotherapy source to the target
treatment location in accordance with the treatment planning. Unintentionally switching
one or more transfer tubes when connecting the conduits to the afterloader for treatment
delivery may thus result in wrong or inaccurate delivery of radiation to the patient.
[0010] Thus, there exists a need for improved brachytherapy position verification systems
and methods capable of confirming the placement of conduits within the patient, for
detecting human error in transfer tube connection, and/or for promoting accurate radiotherapy
source positioning. There also exists a need for a user- and patient-friendly position
verification system and method that is effective, affordable, integrated into the
work flow, and/or able to synchronize data between one or more of the various treatment
planning, treatment delivery, imaging, and/or tracking devices.
[0011] US 2013/0072753 relates to preventing inadvertent actuation of a medical device while it is still
within a lumen of an endoscopic device. The medical device has a detection system
that aids operators in determining whether the distal end of the medical device is
within the lumen or extending out of it. The medical device is a laser fiber, lithotripter,
cauterizing end-effector or another energized device that may damage itself or the
endoscopic device if actuated at the wrong time.
[0012] WO 2014/049477 relates to a treatment device for placing a therapeutic device in a part of the corpus
of a living being. The treatment device comprises an elongated body, which comprises
a channel and an impedance sensor element. The impedance sensor element is for detecting
the presence of the therapeutic device at a specific position within the channel.
Summary
[0013] In accordance with the invention, there is provided a verification system for use
with a brachytherapy treatment delivery system as recited by claim 1.
[0014] Embodiments of the present disclosure are directed to a position verification system.
[0015] In accordance with one embodiment, a treatment location verification system for confirming
the position of a conduit inserted within a patient may include an elongate control
element dimensioned for insertion within the conduit. The control element has a proximal
end and a distal end, and a verification element coupled to a distal region. The verification
element may be configured to detect the presence of a reference marker associated
with the conduit and transmit a signal indicative of the position of the reference
marker relative to the verification element. The system may also include a drive device
coupled to a proximal region of the control element for controlling movement of the
control element through the conduit, a controller configured to receive and process
the signal transmitted by the verification element, and a signal conductor for transmitting
the signal from the verification element to the controller.
[0016] Various embodiments of the treatment location verification system may include any
one or more of the following features: at least one of the drive device and the controller
may be included within an afterloader; the verification element may be further configured
to emit a signal in order to detect the presence of the reference marker associated
with the conduit; the control element may include a wire or a cable; the signal conductor
may be further configured to transmit a signal from the controller to the verification
element; the drive device may include a drum around which at least a portion of the
control element is wrapped; the position verification system may include an electromagnetic
transmitter, and the verification element may include at least one of a coil, a diode,
an optical element, or a semiconductor component; the signal conductor may wirelessly
communicate with the verification element and the controller; and the signal conductor
may include an optical fiber, and the verification element may include at least one
of a photo detector, a camera, an optical waveguide, a wavelength shifter, a scintillator,
or a reflective surface.
[0017] In accordance with a further embodiment, a verification system for confirming the
position of a conduit inserted within a patient comprises: an elongate control element
dimensioned for insertion within the conduit, wherein the control element has a proximal
end and a distal end; a verification element coupled to a distal region of the control
element, wherein the verification element is configured to detect the presence of
a reference marker associated with the conduit and communicate a signal indicative
of the position of the reference marker relative to the verification element, and
wherein the control element is configured to maneuver the verification element along
a length of the conduit; a drive device coupled to a proximal region of the control
element for controlling movement of the control element through the conduit; a controller
associated with the verification element, wherein the controller is configured to
communicate with the verification element; and a signal conductor to conduct the signal
between the verification element and the controller.
[0018] The reference marker may be further detectable by at least one of an imaging system,
a treatment delivery system, or a tracking system when the reference marker is inserted
within the patient. The tracking system may be an electromagnetic or an optical tracking
system. The imaging system may include at least one of a radiography, an X-ray, an
MRI, or an ultrasound system.
[0019] The control element may be included as part of a brachytherapy treatment delivery
system. At least one of the drive device and the controller may be included within
an afterloader. The control element may include a wire or a cable. The drive device
may include a drum around which at least a portion of the control element is wrapped.
[0020] The verification element may be further configured to emit a signal in order to detect
the presence of the reference marker associated with the conduit. The signal conductor
may be further configured to transmit a signal from the controller to the verification
element. The signal conductor may be a wireless connection between the verification
element and the controller. The signal conductor may include an optical fiber for
conducting light between the verification element and the controller and the verification
element may include at least one of a photo detector, a camera, an optical waveguide,
a wavelength shifter, a scintillator, or a reflective surface.
[0021] The verification system may further comprise an electromagnetic transmitter for generating
an electromagnetic field, wherein the verification element includes a coil, and wherein
the verification element is configured to detect a change in the generated electromagnetic
field that correlates to the position of the reference marker relative to the verification
element. Alternatively or in addition, the verification element may include a light-emitting
diode, the reference marker may include a material having a different reflective property
than a reflective property of the conduit, and the verification element may be configured
to detect a change in the reflective property indicative of the reference marker.
[0022] In one embodiment of the present disclosure, a brachytherapy position verification
system for confirming the position of a conduit inserted within a patient may include
an elongate control element having a proximal end and a distal end and dimensioned
for insertion within the conduit, and a verification element coupled to a distal region
of the control element. The verification element may be configured to detect the presence
of a reference marker associated with the conduit and transmit a signal indicative
of the position of the reference marker relative to the verification element. The
control element may be configured to maneuver the verification element along a length
of the conduit. The system may also include an afterloader for delivering a radioactive
treatment to the conduit. The afterloader may include a drive device for controlling
movement of the control element through the conduit and a controller configured to
communicate with the signal transmitted by the verification element. The system may
further include a signal conductor for transmitting the signal from the verification
element to the controller.
[0023] Various embodiments of the brachytherapy position verification system may include
any one or more of the following features: the controller may be configured to communicate
with one or more of an imaging system, a treatment planning system, a treatment delivery
system, and a tracking system; the controller may be configured to integrate the signal
transmitted by the verification element with at least one of imaging data and electromagnetic
tracking data; the verification element may include at least one of a semiconductor
component, a diode, a coil, or an optical element; the controller may be configured
to receive the signal from the verification element; the controller may be configured
to transmit a signal to the verification element; and the afterloader may measure
the distance that the verification element is inserted into the conduit.
[0024] In accordance with a further embodiment, a brachytherapy verification system for
confirming the position of a conduit inserted within a patient comprises: an elongate
control element dimensioned for insertion within the conduit, wherein the control
element has a proximal end and a distal end; a verification element coupled to a distal
region of the control element, wherein the verification element is configured to detect
the presence of a reference marker associated with the conduit and transmit a signal
indicative of the position of the reference marker relative to the verification element,
and wherein the control element is configured to maneuver the verification element
along a length of the conduit; an afterloader for transferring a radiotherapy source
inside the conduit, wherein the afterloader includes a drive device for controlling
movement of the control element through the conduit, and a controller configured to
communicate with the verification element; and a signal conductor for conducting the
signal between the verification element and the controller.
[0025] The controller may be configured to communicate with one or more of an imaging system,
a treatment planning system, a treatment delivery system, and a tracking system. The
controller may be configured to integrate the signal transmitted by the verification
element with at least one of imaging data and electromagnetic tracking data.
[0026] The verification element may include an optical element, wherein the reference marker
has an optical property that is different than an optical property of the conduit,
and the verification element may be configured to detect the optical property of the
reference marker in order for the system to determine the proximity of the verification
element to the reference marker. Alternatively or in addition, the verification element
may include an electronic element or a coil, and the verification element may be configured
to detect a change in an electromagnetic property of the reference marker in order
for the system to determine the proximity of the verification element to the reference
marker.
[0027] In another embodiment of the present disclosure, a method of confirming the position
of a conduit pre-inserted in a patient may include inserting a verification element
within the conduit, moving the verification element distally along a length of the
conduit, and detecting a signal using the verification element, wherein the signal
is indicative of the presence of a reference marker associated with the conduit. The
method may further include transmitting the signal from the verification element to
a controller and processing the signal to determine a position of the reference marker
relative to the verification element. The conduit is pre-inserted in the patient,
such that insertion of the conduit in the patient does not form part of the method.
[0028] Various embodiments of the method may include any one or more of the following features:
the method may further include transmitting data regarding the position of the reference
marker to at least one of an imaging system, a treatment planning system, a treatment
delivery system, and a tracking system; processing the signal may include synchronizing
at least one of imaging data and electromagnetic tracking data with the signal transmitted
by the verification element; the detecting, the transmitting, and the processing may
be repeated as the verification element is moved distally along the length of the
conduit; processing the signal may include determining whether the position of the
reference marker relative to the verification element is within an expected predetermined
distance threshold; the method may further include generating an error signal if the
position of the reference marker relative to the verification element is outside of
the expected predetermined distance threshold; and the method may further include
automatically adjusting delivery of a treatment if the position of the reference marker
relative to the verification element is outside of the expected predetermined distance
threshold.
[0029] Additional objects and advantages of the embodiments will be set forth in part in
the description that follows, and in part will be obvious from the description, or
may be learned by practice of the embodiments. The objects and advantages of the embodiments
will be realized and attained by means of the elements and combinations particularly
pointed out in the appended claims.
[0030] It is to be understood that both the foregoing general description and the following
detailed description are exemplary and explanatory only and are not restrictive of
the claims.
Brief Description of the Drawings
[0031] The accompanying drawings, which are incorporated in and constitute a part of this
specification, illustrate the disclosed embodiments, and together with the description,
serve to explain the principles of the disclosed embodiments. In the drawings:
Figure 1 illustrates an exemplary treatment workflow, according to an embodiment of
the present disclosure;
Figure 2 illustrates a perspective view of exemplary reference markers, according
to embodiments of the present disclosure;
Figure 3A illustrates a perspective view of an exemplary brachytherapy applicator,
according to an embodiment of the present disclosure;
Figure 3B depicts a cross-sectional view of the exemplary brachytherapy applicator
of Figure 3A, according to an embodiment of the present disclosure;
Figure 4 depicts a schematic view of exemplary conduit positioning, according to an
embodiment of the present disclosure;
Figure 5A depicts a schematic view of exemplary components of a position verification
system, according to an embodiment of the present disclosure;
Figure 5B illustrates a schematic view of additional exemplary components of the position
verification system of Figure 5A, according to an embodiment of the present disclosure;
Figure 6 illustrates a schematic view of components of an afterloader-integrated position
verification system, according to an embodiment of the present disclosure;
Figure 7A depicts a schematic view of the positioning of conduits and reference markers,
according to an embodiment of the present disclosure;
Figure 7B graphically depicts signals detected based on the reference marker locations
depicted in Figure 7A, according to an embodiment of the present disclosure;
Figure 8 depicts a schematic view of an exemplary optical position verification system,
according to an embodiment of the present disclosure;
Figure 9A illustrates a schematic view of an electromagnetic position verification
system, according to an embodiment of the present disclosure;
Figure 9B illustrates a schematic view of an electromagnetic position verification
system with an active verification element, according to an embodiment of the present
disclosure;
Figure 9C illustrates a schematic view of an electromagnetic position verification
system with a passive verification element, according to an embodiment of the present
disclosure;
Figure 10 depicts a schematic view of an electromagnetic position verification system,
according to an embodiment of the present disclosure;
Figure 11A depicts a schematic view of the positioning of conduits relative to a target
treatment area, according to an embodiment of the present disclosure;
Figure 11B graphically depicts signals detected based on the target treatment area
location depicted in Figure 11A, according to an embodiment of the present disclosure;
Figure 12A depicts a schematic view of the positioning conduits relative to a marker
located in a target treatment area, according to an embodiment of the present disclosure;
Figure 12B graphically depicts signals detected based on the marker location depicted
in Figure 12A, according to an embodiment of the present disclosure;
Figure 13 depicts a block diagram shown an exemplary workflow interface, according
to a further embodiment of the present disclosure;
Figure 14 depicts a block diagram shown an exemplary workflow interface, according
to a further embodiment of the present disclosure; and
Figure 15 depicts a block diagram shown an exemplary workflow interface, according
to a further embodiment of the present disclosure.
Detailed Description
[0032] Reference will now be made in detail to the exemplary embodiments of the present
disclosure described below and illustrated in the accompanying drawings. Wherever
possible, the same reference numbers will be used throughout the drawings to refer
to same or like parts. For purposes of this disclosure, "proximal" refers to an end
closer to the source of treatment (e.g., afterloader), and "distal" refers to an end
further from the source of treatment. "Radiotherapy source" refers to a radioactive
or x-ray source and encompasses both sources used for therapeutic and non-therapeutic
purposes. "Communication" may refer to receiving signals, transmitting signals, or
both receiving and transmitting signals. Additionally, the term "conduit" may refer
to a catheter, needle, tube, applicator, applicator channel, or any suitable delivery
pathway for a radiotherapy source.
[0033] While the present disclosure is described herein with reference to illustrative embodiments
for particular applications, such as brachytherapy position verification systems for
use with an afterloader, it should be understood that the embodiments described herein
are not limited thereto. Those having ordinary skill in the art and access to the
teachings provided herein will recognize additional modifications, applications, embodiments,
and substitution of equivalents that all fall within the scope of the disclosed embodiments.
For example, the principles described herein may be used with any suitable conduits
(e.g., for use with injection needles, biopsy needles, catheters, applicators) for
any suitable treatment or diagnostic purpose (e.g., brachytherapy, biopsies, or drug
delivery), for any suitable part of the human anatomy (e.g., internal body cavities
or superficial regions), and with either manual or automated delivery (e.g., with
or without the assistance of a mechatronic device like an afterloader). Accordingly,
the disclosed embodiments are not to be considered as limited by the foregoing or
following descriptions.
[0034] Prior to providing a detailed description, the following overview is provided to
generally describe the contemplated embodiments. In one embodiment, a position verification
system may include a conduit having one or more reference markers located along the
length of the conduit. Exemplary conduits include a transfer tube, a catheter, a needle,
a tube, or an applicator, or a channel, catheter, tube, or needle within an applicator.
As is shown in Figure 1, brachytherapy treatment may include treatment preparation,
control, and execution (e.g., one or more of applicator insertion with or without
imaging, treatment planning, treatment delivery, with or without treatment verification).
During treatment preparation, the conduit may be placed within a patient, and the
reference markers associated with the conduit may be detected by a medical imaging
system, such as magnetic resonance imaging (MRI), (computed) tomography (CT), (computed)
radiography (CR), X-ray, elastography, thermography, photo acoustic imaging, tomography,
angiography, optical, near infrared spectroscopy, electromagnetic, nuclear medical,
and/or ultrasound imaging. The reference marker detection data may be transmitted
to a processor for use with the planning treatment software and/or treatment delivery
software. The treatment software analyzes this detection data and determines the two-dimensional
or three-dimensional position of the reference marker (and thus conduit) within the
patient.
[0035] During the treatment control stage, treatment planning may occur, and the precise
dose distribution and dwell positioning may be mapped out, based on the positioning
of the conduits relative to the patient anatomy. During treatment execution, treatment
may be delivered via the conduits, and treatment verification may occur before, during,
and/or after treatment delivery. Though the embodiment of Figure 1 shows a clear,
linear division, the steps may be rearranged or repeated as desired; for example,
treatment control and/or execution may also include imaging, and treatment control
and/or preparation may also include treatment verification.
[0036] Once in place, the verification element is then passed into the one or more conduits,
e.g., during the treatment control and/or treatment execution stage. The verification
element may be configured to detect the reference markers to determine whether the
positioning of the conduit is correct. The path of the verification element through
the conduit may mimic the path that the radiotherapy source will take through the
conduit, so use of the verification element to determine positioning relative to a
reference marker may allow a healthcare provider to determine whether the radiotherapy
source will be correctly positioned. Exemplary embodiments of this system are described
in further detail below.
[0037] As is shown in Figure 2, conduits 1a-1g may include one or more reference markers
2a-2g along the length of the conduit. Reference markers 2a-2g may be located in any
suitable position, e.g., within the walls of the conduit, on an outer surface of the
conduit, on an inner surface of the conduit, may extend from an inner to an outer
surface of the conduit, or any combination thereof. Reference markers 2a-2g may be
located at any location of the conduit, along a side wall of the conduit, or multiple
reference markers may be located in a combination of locations. The reference markers
may be any suitable size, shape, or combination of sizes and/or shapes. For example,
a reference marker may extend partially or entirely around the circumference of the
conduit, either continuously (2a, 2d, 2g), or in a discrete pattern (2c, 2e). Multiple
reference markers may be irregularly spaced along the length of the conduit (2e),
or may be regularly spaced, or may be located on opposite sidewalls of the conduit
(2b, 2f) or at set distances from one another. Additionally, the reference markers
may be embedded within, lie flush with, protrude from, or be recessed within a sidewall
of the conduit, or any combination thereof.
[0038] The reference markers may include, for example, rings, coils, magnets, biodegradable
markers (e.g., polylactide markers detectable using fluorescence), printed patterns,
radio-frequency identification (RFID) elements, openings in the conduit, and/or local
areas of the conduit that are of a different physical configuration than the rest
of the conduit (e.g., a different local material, geometry, or roughness), or any
combination thereof. Exemplary reference markers may include, e.g., a printed code,
such as a barcode (2c', 2g), a metallic ring or coil (2a), a radiopaque printed pattern
(2e), or any suitable combination thereof. Reference markers may be formed of a suitable
material or combination of materials, including, e.g., metal (e.g., a conductive,
magnetic, or ferromagnetic metal), liquid, ink, plastic, ceramic, or glass. In embodiments
in which the conduit is included in an applicator, as shown in Figures 3A and 3B,
portions of an applicator 4 may include one or more reference markers 5. Additionally,
one or more individual channel conduits 6 within applicator 4 may also include one
or more reference markers 5'.
[0039] The one or more reference markers may be located in a predetermined location along
the conduit. For example, the positioning of the reference markers may align with
intended dwell positions of a radiotherapy source fed through the conduit, or may
mark distance increments along the length of the conduit, or other pre-determined
locations of the conduit, or may simply serve as a point of reference. For example,
the larger reference marker in 2f may align with an area of interest, and the smaller
reference marker in 2f may align with an intended dwell position along that target
area. The different sizes or arrangements of reference markers may convey different
types of information and may work best with different types of verification elements.
[0040] Further, the reference markers may be capable of being detected by one or more of
a treatment delivery system, treatment planning system, tracking system, and/or imaging
system. For example, an imaging system may be able to detect a metal ring, which may
also be detectable by means of a coil inside the position verification element and
by using an electromagnetic tracking device, as well as electronics incorporated into
a treatment delivery system. Thus, detection of the reference markers in their respective
locations may provide a way for the different positioning data to be synchronized
and may facilitate communication between the various systems. The systems may also
determine, assess, and/or adjust indirect measurements of the positioning of the reference
marker and associated conduit within the patient. Such coordination and synchronization
may promote the accuracy of treatment delivery and/or treatment planning.
[0041] As is shown in Figure 4, multiple conduits may be spaced relative to each other at
known locations. One or more conduits may include reference markers that align with
or are placed near possible dwell positions, while one or more conduits may include
reference markers that act as a reference for conduit or dwell positioning verification.
In the embodiment of Figure 4, conduits 1b and 1c include position reference markers
2b and 2c, respectively. Conduit 1a includes reference marker 2a, which acts as a
point of reference for determining relative positioning of reference markers 2b and
2c. During conduit insertion, conduits 1a, 1b, and 1c are positioned in or near a
target area and may be positioned in predetermined locations relative to each other.
The reference markers of each conduit may be capable of being detected by treatment
delivery, imaging, and/or tracking systems. Thus, the imaging system may determine
the mutual position of the reference points, an afterloader may place a wire and/or
verification element relative to the reference point to measure positioning, and a
tracking (e.g., electromagnetic tracking) system may check the mutual position of
the conduits. Any deviation of the relative distances and/or data, either within or
between each system, may indicate shifting or movement of one or more conduits. Detection
of the reference markers may provide a constant reference point with which to synchronize
data across the systems. The systems may be separate from each other, may communicate
with one another, or may be incorporated within a single system, e.g., a brachytherapy
system with processing capabilities.
[0042] In embodiments in which multiple conduits are used in the treatment process, each
conduit may have substantially uniform reference marker types and/or positions, or
each conduit may have different reference marker types and/or different arrangements
of reference markers. The differences in reference marker types and/or positions may
indicate different information, e.g., different intended dwell positions and/or may
aid in confirming the identity of each conduit to promote proper connection of the
conduits to the brachytherapy system. For example, the position or type of a first
reference marker in a conduit may identify the conduit, while the position or type
of a second reference marker may be used to determine positional information. For
example, a barcode, rings spaced in a certain pattern, or an RFID reference marker
may identify the conduit, while a different type of reference marker or different
amount of spacing may provide positional information. In conduit 1c of Figure 2, barcode
2c' may identify the conduit, and reference markers 2c may provide positional information.
In some embodiments, each conduit may include a type of reference marker that is different
from the type used in other conduits, and the type of reference marker may identify
the conduit, while the location of the reference marker may be used to provide positioning
information.
[0043] The conduit may be formed of any suitable material, including, e.g., glass, plastic
(with or without fillers, e.g., liquid silicone rubber, polyetheretherketone, polyphenylsulfone,
polyethylene terephthalate, polycarbonate, polyimide, and/or polyoxymethylene), ceramic,
metal (e.g., stainless steel, titanium, nitinol, tungsten) or metal alloys, composite
material with fibers (e.g. epoxy, carbon, polybenzoxazole), or any suitable combination
of materials. These materials may be biocompatible. The conduit may be rigid or flexible,
or may have rigid and flexible portions. Further, the conduit may have any suitable
cross-sectional shape and size, e.g., circular, rectangular, or oval cross-sectional
shape, and may vary in size (e.g., length or width) depending on the desired amount,
and/or rate of dosage to be delivered to a treatment site. In addition, one or more
portions of the conduit may include a suitable shielding material to reduce radiation
exposure of healthy tissue or organs. For example, stainless steel, titanium or tungsten,
or alloys thereof, may be included in portions of the conduit to improve shielding.
[0044] The conduit includes a hollow inner portion dimensioned to receive a radiotherapy
source or a verification element. After the conduit is positioned within a patient,
the verification element may be passed through the hollow inner portion of the conduit
from a proximal end to a distal region. This may occur during, before, or after the
treatment planning stage, the treatment delivery stage, etc., or any combination thereof.
To guide insertion and withdrawal, the verification element may be integrated in or
coupled to a distal region of an elongate control element, e.g., a cable, a fiber,
a foil, a tube, or a wire, which may be pulled and/or pushed proximally and distally
to maneuver the verification element within the conduit.
[0045] The verification element may be configured to detect a reference marker (or vice
versa) and/or may be configured to transmit a signal (e.g., optical or ultrasound
pulses) to a receiving system, which may then be able to determine the position of
the verification element. The verification element may detect or transmit, for example,
an optical (e.g. ultraviolet, infrared) electrical, electromagnetic, magnetic, radio-frequency
(RF), inductive, conductive, or capacitive signal. The verification element may be
either passive (i.e., receive signals) or active (i.e., transmit signals or transmit
and receive signals). In some embodiments in which the verification element is passive,
the reference marker may itself be active and may include, e.g., a diode or other
active signal. Thus, the verification element may be able to detect a reference marker
as it approaches the location of the reference marker, or the verification element
may be used to transmit a signal that may be detected by means of a receiving system
located inside or outside of the patient or within the applicator. The verification
element may be able to detect proximity to the reference marker and/or when the verification
element has reached the location of the reference marker.
[0046] Exemplary verification elements may include one or more cameras, RFID devices, coils,
antennas, diodes, optical fibers, magnets, capacitors, hall sensors, piëzo elements,
photo detectors (e.g., photodiode, photomultiplier, charge-coupled device), light-emitting
diodes, lasers, reflective surface, small microelectronic, microelectromechanical
system (e.g., MEMS-device), semiconductor component, small electronic integrated circuit
(IC), or small photonic integrated circuit (PIC), or any suitable combination thereof.
Further, active verification elements and/or reference markers may include a source
of electricity, e.g., a battery or a wired connection to an electrical source.
[0047] In the embodiment of Figure 5A, a verification element 8 is located at a distal region
of a cable 10. Verification element 8 is electrically coupled via a signal conductor
12 extending through or along cable 10 to a control system 14 coupled to a proximal
end of cable 10. As is shown in Figure 5B, verification element 8 and cable 10 are
inserted into conduit 1. As verification element 8 passes a reference marker 2, verification
element 8 detects the presence of reference marker 2. Verification element 8 then
sends a signal depending on the reference marker to control system 14 via signal conductor
12. Signal conductor 12 may also relay signals to verification element 8. Additionally,
verification element 8 may receive power from control system 14 via either signal
conductor 12 and/or cable 10. For example, an active verification element 8 may receive
power from control system 14 to power verification element 8 and/or transmit a signal,
which may be reflected or altered by reference marker 2, and verification element
8 may detect this signal and transmit the signal to control system 14. In some embodiments,
the verification element may receive power and/or a signal from the control system
14 that then allows it to transmit a signal that can be detected by a separate system.
The separate system may then detect and process the signal of the verification element
to determine the location of the verification element. Additionally, the separate
system may detect an alteration in the signal caused by reference marker 2 so that
the separate system can detect the location of reference marker 2 and verification
element 8.
[0048] Signals may be relayed between verification element 8 and control system 14 on a
continuous, temporary, or intermittent basis. If the signals are intermittently or
temporarily transmitted, the timing may be at regular, spaced-apart intervals, or
may be irregular, for example, increasing in frequency as the verification element
approaches reference marker 2. In some embodiments, verification element 8 may be
electrically coupled to control system 14 by a plurality of signal conductors 12.
In other embodiments, verification element 8 may not be connected to any signal conductors
and may instead wirelessly transmit information to control system 14, or to a separate
system. Exemplary wireless embodiments may include, e.g., radio frequency (RF), telemetry
(e.g., far-field radio-frequency or inductive telemetry), near field communication,
magnetic field, Bluetooth, Zigbee, and/or infrared (IR) technology.
[0049] Control system 14 may include a processor 25 that interprets signals received and
transmitted by verification element 8. Using at least the signals, processor 25 may
determine the spatial positioning of verification element 8 relative to reference
marker 2. In this way, processor 25 may determine whether or not the position of verification
element 8, reference marker 2, and/or conduit 1 is correct, and thus whether the ultimate
location of the radiotherapy source is correct. This processor may also be part of
or may communicate with the treatment imaging, planning, tracking, and/or delivery
systems to share, modify, merge, and/or compare this information.
[0050] Control system 14 may also include a drive system and/or accompanying electronics
for controlling movement of cable 10 and verification element 8 through conduit 1,
which may also be operably coupled to processor 25. Control system 14 may further
include and/or communicate with a system equipped with a display panel or graphical
user interface to display information about the detected signal, including positional
information, to a user. Control system 14 may also include and/or communicate with
a system equipped with a control panel to allow a user to input information, control
the information being processed or displayed, control communication with other systems,
or change the treatment delivery, for example.
[0051] Additionally, control system 14 may be part of a brachytherapy system (e.g., afterloader)
or may be separate from a brachytherapy system. Inclusion within an afterloader may
facilitate use of verification element 8 just prior to, during, or after treatment
delivery. Control system 14 may include a power source, e.g., a replaceable or rechargeable
battery and/or may be configured to connect to a source of power.
[0052] For example, as is shown in the embodiment of Figure 6, drive system 15 may include
a drum/wheel around which cable 10 is wound. Unwinding of the drum may be controlled
by the control system or may be manually controlled. The drum may be operably coupled
to a motor, crank, and/or any suitable automated or manual mechanism for winding and/or
unwinding the drum. Drive system 15 may be part of an afterloader 16, which may control
movement of verification element 8, in addition to delivery of one or more radiotherapy
sources.
[0053] The systems may communicate with each other via communication standards, such as
the DICOM-RT and/or dedicated software and hardware. For example, in operation, the
reference marker data detected by the verification element may be compared to imaging
information, including previously captured or real-time images of the conduit and
reference markers within the patient. Images stored in one or more of the programs
may be communicated and shared. Images of detected reference marker locations may
be compared with the reference marker locations detected by the verification element.
Accordingly, in some embodiments, the verification element may be used in conjunction
with one or more external imaging devices.
[0054] In some embodiments, the verification element may be used separate from imaging devices,
which may allow for position verification in environments in which imaging devices
generally can't be used. This may include specially shielded rooms in which the patient
undergoes radiation treatment. In some embodiments, the verification element data
may be compared with measurement data collected by the afterloader, for example, measurements
regarding the distance that the cable or verification element has been inserted into
the conduit.
[0055] In Figure 7A, three conduits (A, B, C), each with their own pattern of reference
markers 2, are depicted. Though three conduits are depicted in Figure 7A, any suitable
number of conduits (e.g., one or a plurality) may be used. The number of conduits
used in a given embodiment may be determined at least in part based on the target
area location, target area size, patient anatomy, or disease state, for example. Conduits
with reference markers 2 may be detected using a medical imaging system, as is depicted
in Figure 7A. One verification element may be passed through each of the three conduits
one at a time, or multiple verification elements may be passed through the three conduits
at the same time, with one verification element per conduit. One or more verification
elements may be coupled to or integrated in one or more cables (e.g., in or onto a
check cable, additional sensor cable, and/or a cable that also contains the radiotherapy
source). As the verification element passes through each conduit and passes the location
of a reference marker 2, the verification element detects a measurement value indicative
of the presence of the reference marker. These measurement value signals may be communicated
to the control system processor. Exemplary signal output values indicative of the
presence of reference markers is graphically depicted in Figure 7B. Changes (e.g.,
spikes and drops) in signal values as the verification element passes through the
conduits may correlate with the position of the reference markers. Thus, the changes
in measurement values detected by the verification element and transmitted to the
control system processor correlate to the presence of a reference marker. Positioning
of the reference markers, the conduits, and eventually the radiotherapy sources within
the conduits, can be verified in this manner.
[0056] The position verification system may directly measure the reference marker location
positions and/or conduit delivery path with the verification element and may verify
whether the values of Figure 7B match the image of Figure 7A. Accordingly, the position
verification system may be able to synchronize the location of the reference marker
positions shown in Figure 7A with the verification element data shown in Figure 7B.
The position verification system may also synchronize positional and/or imaging data
from one or more of the diagnostic, planning, treatment, tracking, and/or delivery
systems. For example, positioning may further be synchronized with measured values
from an afterloader, such as the length of the verification element cable that has
been inserted into the conduit.
[0057] If the position verification system detects a mismatch between the positioning detected
by the verification element and the expected positioning location, the processor may
send a signal indicating to the healthcare provider that something is wrong. This
signal may be in the form of a visual and/or an audible signal, for example. Generating
such a signal may promote the accuracy of treatment delivery by notifying a healthcare
provider of a potential discrepancy prior to or during treatment delivery.
[0058] In some embodiments, when a deviation is detected, the system may not make any changes
or generate any signal, for example, if the deviation is within a certain, predetermined
threshold of tolerance. In this case, if position verification is being performed
during treatment delivery, delivery may continue, or if position verification is being
performed prior to treatment delivery, delivery may occur as planned.
[0059] If a deviation is detected that is outside a threshold level of tolerance, then the
system may prevent or halt the delivery of radiotherapy treatment until after the
discrepancy is corrected. The system may be configured to automatically fix the deviation
(e.g., by adjusting or skipping dwell positions, or dwell times, or dosage), or the
error may require manual fixing. In some embodiments, the detection of a deviation
may result in a return to the treatment planning stage to adapt the plan to the current
situation, or additional imaging may be taken to visibly assess the deviation, and,
if required, adapt the treatment plan. Instead of, or in addition to, adjusting the
plan, the conduits may be repositioned. If no deviations are detected, or if no deviations
above a predetermined threshold level of tolerance are detected, treatment may be
delivered and/or treatment delivery may continue. If a deviation is detected during
post-treatment verification, future treatment plans or fractions may be altered. In
this way, the verification system may promote more safe and accurate treatment delivery
and may provide a convenient and more accurate method to verify if the radiotherapy
source will be placed in the correct conduit and at the correct position in the conduit
relative to the target area.
[0060] In some embodiments, the position verification system may also be able to detect
a deviation between the expected conduit identity and the actual identity of the conduit
in which the verification element is deployed. If a deviation is detected, the system
may send a signal indicating to the healthcare provider that something is wrong. This
may protect against human error, for example, in mixing up the transfer tube connections.
In some embodiments, if the system detects that something is wrong, the system may
prevent delivery of the radiotherapy source to the conduit until the discrepancy is
corrected, and this correction may occur manually or automatically. The system may
include one or more components and one or more processors in communication with the
components and/or the other processors. For example, a processor may be included within
or in communication with a computer, a detector, an afterloader, or any other suitable
component of a brachytherapy system. Exemplary embodiments of position verification
systems are explained in further detail below.
[0061] In some embodiments, the verification element may be able to send a signal, which
the reference marker may reflect, and this reflected signal may be detected by the
verification element. In some embodiments, the reference marker may be able to send
a signal, which the verification element may reflect, and this reflected signal may
be detected by the reference marker. In still other embodiments, the verification
element may send a signal, which the reference marker may receive. The reference marker
may then send information regarding the received signal to a controller. And, in other
embodiments, the reference marker may send a signal, which the verification element
may receive. The verification element may then send information regarding the received
signal to a controller, e.g., via the signal conductor.
[0062] In an exemplary optical embodiment, the verification element may be configured to
detect a comparative difference in an optical property between the conduit and the
reference marker, or vice versa. For example, the amplitude, phase/delay, frequency/wavelength,
refraction, interference, or other signal property or combination of properties could
be detected by either the verification element or the reference marker. In the embodiment
of Figure 8, optical verification element 8 may detect a change in light reflection
as it approaches, reaches, or passes reference marker 2 of conduit 1. Optical verification
element 8 may include, for example, one or more of a photo detector (e.g., photodiode,
photomultiplier, charge-coupled device), a camera, a laser, an optical fiber, an optical
waveguide, a reflective surface, a lens, a prism, a filter, a beam splitter, a polarizer,
grating, or any suitable combination thereof. Suitable reference markers for use with
an optical verification element may include, for example, a radiopaque marker (e.g.,
a radiopaque marker and/or a printed ink), a locally different material (e.g., a locally
darker or lighter and/or more or less dense material), or a locally more or less reflective
material (e.g., a metallic and/or polished surface). In an exemplary embodiment, a
radiopaque ink may be printed on a surface of a plastic conduit. Further, if verification
element 8 is passive, reference marker 2 may emit light and may include, for example,
fluorescence material or light emitting fibers or diodes.
[0063] In optical embodiments, a signal conductor may include, for example, one or more
electrical cables or wires, or one or more optical fibers, or a combination thereof.
The signal conductor may power either the reference marker or the verification element
or may be used for transmitting signals. In some embodiments, the reference marker
may be able to use the signal energy (e.g., light or electromagnetic energy) from
the verification element for powering. The signal conductor may connect the verification
element and/or the reference marker with control system 14 and may be located within
the walls of the conduit, external to the conduit, or within the conduit. In some
embodiments, signals may be transmitted wirelessly between verification element 8
and control system 14 or another system 26.
[0064] In the embodiment of Figure 8, an optical fiber may transmit light from control system
14 to verification element 8, and a reflective surface 17 (e.g., a mirror and/or other
optical elements) may direct, magnify, and/or or focus the light onto a surface (e.g.,
wall) of conduit 1. The wall of conduit 1 may reflect light back to reflective surface
17 and cable 10 may transmit the reflected data through the optical fiber to control
system 14, which may contain hard-wired, wireless charged, or battery-operated electronics
and optical elements for emitting and detecting light (e.g., one or more lamps, LEDs,
lasers, photo detectors, diodes, photomultipliers, lenses, filters), and associated
processor 25. The system may determine a characteristic of the reflected light, for
example the frequency, intensity, angle of incidence, or spectrum. When verification
element 8 approaches, reaches, or passes reference marker 2, the characteristic of
the reflected light changes, and processor 25 may calculate the positioning of verification
element 8 relative to reference marker 2 based at least in part on this change.
[0065] In the embodiments of Figures 9A-9C, electromagnetic position verification systems
are depicted. Verification element 8 may be either active or passive. In an active
embodiment, as shown in Figure 9B, verification element 8 may generate an electromagnetic
field 18 and detect a deviation in the signal that is indicative of a reference marker
2 as it approaches, reaches, or passes reference marker 2. In an exemplary active
embodiment, a conductive reference marker may form a ring around the circumference
of the conduit, or a plurality of reference markers may be located across from one
another on the opposite walls of the conduit. The active verification element 8 may
generate an electromagnetic field 18 and detect a signal change caused by the conductive
reference markers as it approaches, reaches, or passes through the reference markers.
A passive verification element may not generate an electromagnetic field and may instead
only detect a signal. In the embodiment of Figure 9C, a separate electromagnetic transmitter
20 may generate an electromagnetic field, and verification element 8 may detect a
change in one or more signal characteristics when it approaches, reaches, or passes
by a reference marker 2. In some embodiments, the verification element may be able
to switch between an active mode and a passive mode.
[0066] The position verification system of Figure 10 includes an electromagnetic transmitter
20 for generating an electromagnetic field to be detected by verification element
8. The signal detected by verification element 8 may then be transferred by signal
conductor 12 to a processor and/or drive electronics. An exemplary electromagnetic
tracking system is the Aurora® Electromagnetic Measurement System of NDI. Verification
element 8 may include one or more coils, e.g., induction coils, and the switching
magnetic field may induce changing currents in the coil that allow the 3D position
of the coil to be detected. These signals received by verification element 8 may be
transmitted to the control system either wirelessly or via a signal conductor 12 and
may be interpreted by the control system processor. For example, a metallic reference
marker, e.g., a ferromagnetic or conductive reference marker, may cause a local disturbance
in the electromagnetic field, and this disturbance may be detected as verification
element 8 approaches, reaches, and/or passes by this reference marker.
[0067] The control system may include (drive) electronics with a switching unit 21. In a
first position, depicted in Figure 10, switching unit 21 may connect verification
element 8 with the electronics of the electromagnetic tracking system to determine
the 3D position of the verification element (i.e., by completing the circuit between
point X and point Y). In a second position, verification element 8 may be connected
with the reference marker detection electronics when switching unit 21 completes the
circuit between point X and point Z. The switching unit may switch between the two
or more positions, optionally connecting the verification element with either the
electromagnetic tracking system or the reference marker detection electronics. The
switching may occur at any suitable rate, and the rate of switching may be regular
or irregular. Further, the rate of switching may be manually controlled by a user
or may be automatically controlled by control system 14. This switching configuration
may integrate an electromagnetic tracking system with the position verification system
and allow the reference markers, the electromagnetic tracking data, and the dwell
positions of the verification element to be merged and/or synchronized into a single
two-dimensional or three-dimensional spatial positioning database. When the reference
marker locations are also known in images (either real-time or stored images), these
images may also be merged/synchronized to the same two-dimensional or three-dimensional
coordinates. To merge three-dimensional data, at least three reference points may
be required, while two-dimensional tracking may require fewer coordinates. The electromagnetic
tracking system may include a sensor with multiple Degrees-Of-Freedom, e.g., 3DOF
or more, and exemplary systems may use two, three, or more reference points.
[0068] In some embodiments, the function of the verification element and the reference markers
may be inverted. For example, the verification element may emit/transmit signals,
and the reference markers included in the conduit may receive those signals. The reference
markers may communicate with the control system (either wirelessly or via one or more
signal conductors) and may transmit information about the received signal. Thus, the
reference markers may detect the approach of an emitted signal, instead of vice-versa,
and the reference marker positioning may be verified in this manner.
[0069] Further, in some embodiments, a single verification element cable may include multiple
verification elements. This configuration may provide redundancy, which may promote
more accurate verification. In some embodiments, different sensors on a single cable
may respond to different reference marker types included in the conduit. For example,
if a single conduit includes a plurality of different reference markers (e.g., barcode,
coding, or RFID conduit identification marker and separate positional reference marker),
a single cable with multiple verification elements may be able to detect information
from both types of reference markers. In such embodiments, each verification element
may be connected to its own signal conductor, each verification element may share
a signal conductor, each sensor may be wireless, or any suitable combination thereof.
[0070] In some embodiments, tissue of the patient may itself be used as a reference marker,
and a verification element and conduit may be configured to directly detect this tissue.
Either healthy or diseased tissue may be used as a reference. For example, a diseased
portion of the tissue may have different reflective properties, may sit in a specific
relative location, or may lie in a different plane. Likewise, a different portion
of healthy tissue may have different reflective properties, may sit in a specific
relative location, or may lie in a different plane.
[0071] In the embodiment of Figures 11A and 11B, a transparent conduit 1 may be inserted
into a patient's body in or near a tissue (e.g., Target Volume) area 23. As is shown
in Figure 11A, an optical verification element 8 may be inserted into conduit 1. Verification
element 8 may be configured to emit and/or detect light. Tissue area 23 may reflect
light differently than the surrounding area and/or tissue, and when verification element
8 approaches, reaches, and/or passes by tissue (or target treatment) area 23 in transparent
conduit 1, verification element 8 may detect a change in the reflected light that
is indicative of tissue area 23.
[0072] Figure 11B shows an exemplary graphical depiction of the sensed optical data. As
verification element 8 approaches a region of conduit 1 adjacent tissue area 23 (designated
with symbol '*'), a property of the reflected light detected by verification element
8 may change, as is shown in Figure 11B. This change may remain steady, may decrease,
or may increase as verification element 8 passes tissue area 23 until verification
element 8 begins to move past tissue area 23. When verification element 8 moves out
of range of tissue area 23 (designated with symbol '#'), the property of reflected
light may return to baseline measurements. This change in detected light property
may be gradual (as is shown in Figure 11B), or may occur more abruptly, for example,
depending on the light property measured, the sensitivity of verification element
8, the transparency of conduit 1, patient anatomy, and/or the local properties around
the conduit.
[0073] It is also possible to use the verification element to detect the tissue around the
conduit before, during, and/or after treatment delivery to verify any deviations (e.g.,
shifts of conduits related to tissue and/or tissue responses caused by radiation treatment).
[0074] In some embodiments, one or more reference markers 2 may be placed directly in or
around a target tissue area (e.g., in or near an organ at risk, in a body cavity,
on the skin of the patient, or in/at a tissue or body support like a patient table),
rather than being associated with a conduit, as shown in Figures 12A and 12B. The
tissue of the patient may be marked by applying or embedding substances with physical
properties that are different than those of the surrounding environment. For example,
one or more liquids or solutions may be injected into or painted onto the tissue,
or one or more permanent or temporary solid markers may be implanted into or onto
the tissue. Exemplary markers may include fluorosensors, fluorescent dyes such as
indocyanine green, biodegradable markers, and/or (bio)medical tracers that bind to
cancerous tissue or react to (gamma) radiation applied during treatment delivery or
verification.
[0075] Similar to the process described above in reference to Figures 11A and 11B, in Figures
12A and 12B, a conduit 1 may be inserted into a patient's body in or near a tissue
23 (e.g., Target Volume) area that has been marked with reference marker 2. An optical
verification element 8 may be inserted into conduit 1. The conduit may be optically
transparent (e.g., if an optical signal is used) and/or may be formed of a material
that allows a signal to pass through the conduit in order to pass between verification
element 8 and reference marker 2. Verification element 8 may be configured to emit
and/or detect light, and tissue marker 2 may reflect light differently than the surrounding
area and/or tissue. When verification element 8 approaches, reaches, and/or passes
by the area of reference marker 2 associated with the tissue, the verification element
may detect a change in the reflected light that is indicative of tissue marker 2.
[0076] Figure 12B shows an exemplary graphical depiction of the sensed reference marker
2 associated with the tissue. As verification element 8 approaches a region of conduit
1 adjacent reference marker 2 associated with tissue area 23 (designated with symbol
'*'), a property of the reflected light detected by verification element 8 may change,
as is shown in Figure 12B. This change may remain steady, may decrease, or may increase
as verification element 8 passes reference marker 2 associated with tissue area 23
until verification element 8 begins to move past reference marker 2. When verification
element 8 moves out of range of reference marker 2 (designated with symbol '#'), the
property of reflected light may return to baseline measurements. This change in detected
light property may be gradual (as is shown in Figure 12B), or may occur more abruptly,
for example, depending on the light property measured, the sensitivity of verification
element 8, the transparency of conduit 1, patient anatomy, and/or the local properties
around the conduit. As will be recognized by one of skill in the art, the property
changes of other, non-optical signal types may also be used to detect reference marker
2.
[0077] Though optical embodiments are described in the above examples, any suitable signals,
reference markers, and verification elements may be used, so long as the signal type
is compatible with the type of tissue marker implanted may be used. For example, electromagnetic
or ultrasound signals may be used, and the reference markers may interact with the
signals to cause a detectable change. In an exemplary ultrasound embodiment, verification
element 8 may emit sound waves, and reference marker 2 may cause changes in the sound
waves that may then be detected, e.g., by verification element 8 or a separate system.
[0078] Figures 13, 14, and 15 provide an overview of exemplary brachytherapy systems that
use a verification element to detect the location of conduits that will be used to
deliver treatment in order to promote more accurate dose delivery. In the embodiment
of Figure 13, the verification element communicates with an afterloader regarding
the detected position of one or more reference markers, which may be used to determine
the location of one or more conduits. A tracking system may also communicate with
the verification element in order to determine the location of the reference marker(s).
Based on this information, system 27 may determine whether the conduits are located
in the intended location, or, if there is a deviation from the intended location,
whether the actual location is within an acceptable threshold of deviation. To help
in this determination, the controller may communicate with an imaging data source
to compare the detected location of the conduits with an image of the conduits within
the body or to compare the detected location of the conduits with an image of the
surrounding body structures. The image may have been taken at an earlier step, e.g.,
during treatment preparation or planning, or may be taken during the verification
procedure. A controller may act as the interface between the various components of
system 27, controlling communications between the components and/or controlling the
actions of one component based on signals received from that component, another component,
or based on data received from multiple components.
[0079] As is shown in Figure 14, a system 28 may include a drive unit and verification element
electronics for controlling movement of the verification element relative to the conduits
and/or reference markers. These components may be independent from an afterloader
device, or may be included in an afterloader device, and may work with a tracking
system to determine the location of the verification element relative to the reference
marker(s). All three components may be in communication with the verification element,
and the controller may adjust the drive unit or the electronics based on information
gleaned from the verification element, the tracking system, the drive unit, or the
verification element electronics. Based on this information, system 28 may determine
whether the conduits are located in the intended location, or, if there is a deviation
from the intended location, whether the actual location is within an acceptable threshold
of deviation. To help in this determination, the controller may communicate with an
imaging data source, as describe in system 27 of Figure 13. Further, the controller
may communicate with a planning system to further determine whether the intended dose
distribution will be achieved within an acceptable threshold based on the actual location
of the reference markers and conduits that is detected by the verification element.
Additionally, as is shown in system 29 of Figure 15, the controller may also communicate
with a delivery system to adjust the actual delivery of treatment, if desired, based
on the actual location information detected.
[0080] Although a hierarchical relationship is shown in the exemplary figures, any component
may interact directly with any other component, or, as is show, one or more of the
components may be routed through a controller. Additionally, one or more components
may be housed within the same structure, e.g., an afterloader, or the components may
be located separate from each other or even remote from each other, and the components
may be connected to each other wirelessly, through hard wired connections, or a combination
of the two. For example, a remote computer database may wirelessly communicate with
and control the other components, or the controller may be included within an afterloader
device. Further, control of the components may be automatic, based on pre-programmed
input and feedback from the components, or control of the components may be manual,
e.g., through user input. Even if the components are automatically controlled, a user
may be able to alter or override the automatic adjustments.
[0081] The many features and advantages of the present disclosure are apparent from the
detailed specification, and thus, it is intended by the appended claims to cover all
such features and advantages of the present disclosure that fall within the scope
of the present disclosure. Further, since numerous modifications and variations will
readily occur to those skilled in the art, it is not desired to limit the present
disclosure to the exact construction and operation illustrated and described, and
accordingly, all suitable modifications and equivalents may be resorted to, falling
within the scope of the present disclosure. The invention is defined in the claims,
other embodiments being merely exemplary.